FIGURE 3.

Sequence conservation for SpoIID from C. difficile, B. anthracis, and B. subtilis and key residues. The sequences for CdSpoIID, BaSPoIID, and BsSpoIID are aligned and numbered according to the secondary structure of CdSpoIID. The sequences are colored according to the conservation. As indicated in the legend, the residues of CdSpoIID that make interactions with the two NAG₃ molecules and the zinc atom are indicated with orange and blue bars, respectively. The residues that have been tested by alanine substitution in CdSpoIID (this work) and BsSpoIID (1, 4) are indicated with black bars. The red bars indicate the mutations with a phenotype.